Introduction: Mass casualty events (MASCAL) are on the rise globally. Although natural disasters are often unavoidable, the preparation to respond to unique patient demands in MASCAL can be improved. Utilizing telemedicine can allow for a better response to such disasters by providing access to a virtual team member with necessary specialized expertise. The purpose of this study was to examine the positive and/or negative impacts of telemedicine on teamwork in teams responding to MASCAL events. Methods: We introduced a telemedical device (DiMobile Care) to Forward Surgical Teams during a MASCAL simulated training event. We assessed teamwork-related attitudes, behaviors, and cognitions during the MASCAL scenario through pre-post surveys and observations of use. Analyses compare users and nonusers of telemedicine and pre-post training differences in teamwork. Results: We received 50 complete responses to our surveys. Overall, clinicians have positive reactions toward the potential benefits of telemedicine

further, participants report a significant decrease in psychological safety after training, with users rating psychological safety as significantly higher than non-telemedicine users. Neither training nor telemedicine use produced significant changes in cognitive and behavioral-based teamwork. Nonetheless, participants reported perceiving that telemedicine improved leadership and adaptive care plans. Conclusions: Telemedicine shows promise in connecting Forward Surgical Teams with nuanced surgical expertise without harming quality of care metrics (i.e., teamwork). However, we advise future iterations of DiMobile Care and other telemedical devices to consider contextual features of information flow to ensure favorable use by teams in time-intensive, high-stakes environments, such as MASCAL.